The invention relates to catheters used to monitor blood pressure within the femoral artery of patients.
Catheters connecting to blood vessels are used primarily to monitor blood pressure in real-time. When a catheter is inserted into the femoral artery it is done so at a low angle such as 40 to 60 degrees above the skin surface. As the catheter cannula obtains altitude above the patient""s body, the cannula is attached to monitoring equipment. The connection point to the monitoring equipment is a place where the catheter will at times shear away from the monitoring equipment, which may result in loss of blood from the patient if the catheter cannula is not quickly removed and/or clamped by medical personnel. The likelihood of shearing is dependent in part upon the firmness of the cannula (or hose) with a firmer cannula more likely to shear. Also, kinking of the cannula may occur, in part, because of the shallow entry angle of the catheter into the patient and movement of the patient""s limbs or the catheter itself while obtaining blood samples.
Attempts have been made to use pediatric internal jugular catheters with the femoral artery. This type of catheter cannula also easily shears at the hub causing the catheter cannula to fail because it exits the hub horizontally and then dives beneath the skin into the artery in a somewhat vertical orientation. The pediatric internal jugular catheter also has a long soft Teflon hose, which leads to two additional problems. The length requires that the insertion point be some distance from the hub, which leads to a greater chance of kinking and other problems that may occur when a hose runs for an extended distance unprotected. The second problem is that Teflon is too soft and will collapse in on itself when blood is drawn from the catheter because of the applied suction forces within the hose from the syringe drawing blood. Another problem associated with catheters in general is that it is difficult to obtain accurate blood pressures readings when right angles or kinking occurs in the hose containing the patient""s blood, because the kinks and right angles cause turbulence within the blood residing in the cannula.
Usually a catheter is inserted using a needle within a lumen of a cannula. When the needle penetrates the vessel, the blood pressure in the vessel will cause blood to flow up the needle bore and into translucent tubing around the top of the needle. The practitioner verifies the penetration of the vessel by looking for blood xe2x80x9cflashbackxe2x80x9d in the tubing. The needle is withdrawn from the catheter, and the cannula is preferably advanced within the blood vessel to a desired position sometimes with the aid of a guide wire.
Notwithstanding the usefulness of the existing catheters, a need exists for a more dependable and durable catheter that easily attaches to patients and provides real-time accurate blood pressure of the patient.
This invention solves the ongoing problems of attaching a catheter to a patient and obtaining real-time accurate blood pressure. The invention while addressing the problems of the prior art obtains advantages that were not achievable with the prior art devices.
The present invention relates to a catheter capable of being inserted into a variety of veins and arteries as needed by medical personnel who wish and need to monitor a patient""s blood pressure in real-time and/or to take regular blood samples from the patient. The invention preferably includes a hub and a cannula running through the hub. The hub preferably provides a port through which to pass a needle and an insertion wire into the cannula and a connector at one end of the cannula/hub to attach to medical equipment. The port may also be used to insert a syringe for obtaining blood samples from the blood present within the hub. The hub preferably includes a passageway that runs from the connector to an exit point through which the cannula travels. The passageway preferably includes a gentle bend to reduce and/or prevent turbulence. The cannula preferably extends from the hub such that it may be inserted into a patient""s blood vessel.
An object of this invention is to improve the reliability and accuracy of real-time blood pressure readings.
Another object of this invention is to produce an even and accurate transmission of the blood pressure wave.
Another object of this invention is to lengthen the life span of an inserted catheter by protecting the catheter at the skin insertion site.
Another object of this invention is to increase the ease in which blood samples are taken from patients.
An advantage of this invention is a more secure attachment of the catheter to the patient.
Another advantage of this invention is the durability of the catheter leading to a longer life span for the catheter.
Another advantage of this invention is a lower profile for the device.
Another advantage of this invention is the prevention of turbulence within the catheter.
Given the following enabling description of the drawings, the method should become evident to a person of ordinary skill in the art.